Canonical has made improvements to the Unity desktop interface in its Ubuntu distribution of the Linux operating system. Unity 3D is the standard User Interface (UI) that runs under Ubuntu 11.10, which is the newest release. Unity 2D, which is the optional UI, displays a slightly simpler desktop. Moreover, depending on the graphics hardware and drivers on your PC, Unity 2D might be noticeably faster than Unity 3D. This document compares Unity 3D with Unity 2D, and explains how to switch between them.
Note: If the graphics hardware and drivers on your PC are too old and/or too slow to support Unity 3D, you can run only Unity 2D.
Comparing Unity 3D and Unity 2D – The differences between Unity 3D and Unity 2D are generally minor; you might not even notice them. Unless you have a separate, high-power graphics card, Unity 2D provides much faster performance than does Unity 3D. For example, you might not be able to play full-screen videos until you switch to Unity 2D.
You can quickly determine whether your PC is running Unity 3D or Unity 2D. Simply click the “Dash home” icon (a small Ubuntu logo), and then click “More Apps” to display either of the first two images above, which show the most obvious differences between the Unity 3D and Unity 2D desktop displays:
* – If your PC is running Unity 3D, your desktop displays most icons with shadows as shown in the first image above. Also, Unity 3D grays out the launcher.
* – If your PC is running Unity 2D, your desktop displays all icons without shadows as shown in the second image above. Also, Unity 2D does not gray out the launcher.
Note: Unity 2D currently does not provide access to desktop help. Until Canonical corrects this, you can go to Ubuntu Support.
Switching Between Unity 3D and Unity 2D – You can switch between Unity 3D and Unity 2D only by restarting your PC, and then changing your session type while logging in to Ubuntu 11.10. To switch between Unity 3D and Unity 2D, do the following:
1 – Verify that you are not already running the Unity session type to which you plan to switch. As I explain in the section above, you can quickly determine which Unity you are running.
2 – Restart your PC, which displays a login frame similar to the third image above.
3 – Click the gear icon (at the upper right) to display a menu of session types.
4 – Select either Ubuntu (Unity 3D) or Ubuntu 2D (Unity 2D).
Note: Your session type is modal. For example, if you select Ubuntu 2D, your PC stays in Unity 2D each time you log in, until you use this procedure to switch back to Ubuntu (Unity 3D).
5 – Type your password and then press “Enter” to log in to Ubuntu 11.10.
Source:
Ethan C. Nobles, “Unity Much Improved in Ubuntu 11.10″, First Arkansas News